Questions and Answers
What is a molecule?
The smallest part of a substance.
What is the cell membrane?
The part of the cell that substances move in and out of.
What does selectively permeable mean?
Some substances can pass through the cell membrane and some cannot.
How do most molecules move?
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What is diffusion?
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Does diffusion use the cell's energy?
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What is passive transport?
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Is diffusion a kind of passive transport?
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Where do molecules move from during diffusion?
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Where do molecules move to during diffusion?
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What is the goal of diffusion?
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What is an example of diffusion?
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What is another example of diffusion?
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What are two kinds of passive transport?
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Why is osmosis considered a kind of diffusion?
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What is active transport?
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Where do molecules move from in active transport?
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Where do molecules move to in active transport?
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What are two ways that the cell moves things by active transport?
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What does engulf mean?
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Study Notes
Passive and Active Transport
- Molecule: The smallest unit of a substance, essential for understanding cellular interactions.
- Cell Membrane: Semi-permeable barrier; regulates the entry and exit of substances in and out of the cell.
- Selectively Permeable: Describes the cell membrane's ability to allow certain substances to pass while blocking others.
Diffusion
- Movement Mechanics: Molecules generally move from crowded (high concentration) areas to less crowded (low concentration) areas.
- Definition: Diffusion is the process of molecules being transported from high to low concentration.
- Energy Usage: Diffusion does not require cellular energy, classifying it as a type of passive transport.
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Examples of Diffusion:
- Dissolving a sugar cube in water.
- Spraying perfume, allowing scent molecules to spread throughout the air.
Osmosis
- Relation to Diffusion: Osmosis is the specific case of diffusion that involves the movement of water across a selectively permeable membrane.
- Types of Passive Transport: Includes both osmosis and general diffusion.
Active Transport
- Definition: The process of moving materials across the cell membrane using cellular energy, essential for maintaining concentration gradients.
- Concentration Flow: In active transport, molecules move from areas of low concentration to areas of high concentration.
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Mechanisms:
- Transport Proteins: Specific proteins assist in moving substances against their concentration gradient.
- Engulfing: The process of surrounding and enclosing substances for transport.
Additional Terms
- Engulf: Means to surround or enclose, particularly in the context of cellular mechanisms for active transport.
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Description
Explore the fundamental concepts of passive and active transport in cells. This quiz covers key mechanisms such as diffusion and osmosis, highlighting their roles in cellular function and the properties of the cell membrane. Test your understanding of how substances move in and out of cells without energy expenditure.